Car-roof



(No Model.)

C. H. KOYL,v

GAR ROOF.

110.436,361. Patented Sept. 16, 1890.

WMM/essay 3M/uente@ UNITED STATES PATENT OFFICE.

CHARLES IIERSCHEL KOYL, OF EASTON, PENNSYLVANIA.

CAR-ROOF.

SPECIFICATION forming part of Letters Patent N o. 436,361, datedSeptember 16, 1890.

Application filed January 30, 1890. Serial No. 338,678. (No model.)

To all whom may concern:

Be it known that I, CHARLES HEESCHEL KOYL, of Easton, in the State ofPennsylvania,have invented a new and useful Improvement in Car-Roofs, ofwhich the following is a specification.

My invention is designed to improve the interior lighting of railwaycars and like structures. Under the plan at present in vogue, in whichlights, whether gas-burners, electric lamps, or oil-lamps, are usuallystrung along the car at intervals in the line of the longitudinal centerof the car and at a short distance below the ceiling, or that portion ofit which is formed by the central raised portion of the car-roof, muchof the light from the burners or lamps is lostin the ceiling, and fromthis and other causes the car is usually insufficiently lighted, to theconsequent discomfort of the passengers. To remedy this defect I makethe car-roof, or at least the interior face of the car, parabolic orapproximately parabolic in cross-section. This parabolic contour may, ifdesired, 'be given to the whole of the ceiling from side to side of thecar; but in practice I have found it sufficient to confine this shape tothe dome or central raised portion of the roof,l under which the lampsor burners are commonly placed, and this latter plan I prefer. Theparabolic shape imparted to the ceiling is crosswise of the car. I donot care for any longitudinal curvature of this character. The object isto reflect in the direction of passengers the light which wouldotherwise be lost in the ceiling, and for this purpose only thecrosswise parabolic curvature is essential. In conjunction with a roofof this shape I employ lamps or illumihating-burners, which are placedat intervals apart at the focal distance from the ceilingthat is to say,in the line of the foci of the parabolic curves which give the contourto the ceiling. It is in this combination of a car roof or ceiling.parabolic or approximately so in section, with lights located at focaldistance therefrom, that my invention essentially is comprised. Underthis arrangement the reiected rays are substantially parallel with oneanother, and are thrown directly down upon the passengers, and in thisway I find that with the same lamps the amount of light available forpassengers is about double that which is available when the ordinary carceiling or roof is employed. The parabolic surface of the ceiling is ofcourse so made as to be a reflector, and I prefer that this surfaceshould be slightly corrugated, as indicated, for example, in my LettersPatent No. 410,598, of September 10, 1889. The character of the liningof the roof Which furnishes the reflecting-surface is, however,immaterial. A plain white lining of any suitable material answers verywell.

In the accompanying drawing I have illustrated a cross-section of thebody of acar containing my invention, that portion of the interior ofthe car beyond the plane of section being shown in perspective. Inthiscase the parabolic curvature is confined to the interior of the domeor raised central portion A of the car-roof. The interior surface orceiling of this portion of the roof is parabolic, or approximately so,in cross-section, as shown by the curve a. There is no longitudinalcurvature to it. In the line of the foci of the innumerable paraboliccurves which make up the ceiling are placed, at suitable intervalsapart, the incandescent or other lamps B, the light-giving portion ofthe lamps being at focal distance from the ceiling, this focal distancebeing determined by the aid of wellknown formulae. Under thisarrangement the upward rays from the lamps, which otherwise would belost in the ceiling, are, as indicated by the dotted lines, reflecteddownner as to aid materially the direct downward rays, and, as beforesaid, to about double the light available for passengers.

I-Iaving now described my'invention and the manner in which the same isor may be carried into effect, what I claim, and desire to secure byLetters Patent, is-

1. A car-roof the interior surface or ceiling of which is formed as areiiecting-surface of parabolic shape, or approximately so, in crosswardnearly in parallelism, and in such mansection, or erosswise of the earonly, substanfocal distances therefrom, substantially as tially as andfor the purposes hereinbefore and for the purposes hereinbefore setforth. xo

set forth. In testimony whereof l have hereunto set 2. A ear-roof theinterior surface or ceiling my hand this 28th day of January, 1890.

of which is formed as a reflecting-surface of CHARLES HERSCHEL KOYL.

parabolic shape, or approximately so, in oross- Witnesses: v

Section, or erosswse of the oar only, in oorn- J. BRUNNER,

hnaton with lamps or burners located at J. W. LATTIG.

